US3916983A

US3916983A - Molding machine

Info

Publication number: US3916983A
Application number: US429543A
Authority: US
Inventors: Edward D Abraham
Original assignee: Individual
Current assignee: Dependable Foundry Equipment Co Inc
Priority date: 1974-01-02
Filing date: 1974-01-02
Publication date: 1975-11-04
Anticipated expiration: 1992-11-04

Abstract

A molding machine comprises a table for supporting a mold pattern and a mold. The cylinder is located beneath the table. A first piston is located within the cylinder and is movable vertically therein. A second piston is carried within the first piston and is interconnected with the table and with the first piston so that on vertical movement of the first piston the second piston and table likewise move vertically. A third piston is located within the second piston and is movable relative to the table and strikes the table effecting a jolting thereof. The second piston is also movable vertically to effect a jolting of the table.

Description

i United States Patent Abraham Nov. 4, 1975 MOLDING MACHINE [76] Inventor: Edward 11. Abraham, 6695 Fairview 'f Road, B re cksvine, Ohio 44141 Asszstant Examiner-John S. Brown 22 Filed: an. 2 1974 21 A l N :29 54 3 [57] ABSTRACT PP A molding machine comprises a table for supporting a mold pattern and a mold. The cylinder is located be- [52] US. Cl. 164/206; 164/39 neath the table. A first piston is located within the cyl- [51] Int. Cl. B22C 15/30 inder and is movable vertically therein. A second pis- Fleld Search ton is carried within the first piston and is intercon- 39 nected with the table and with the first piston so that on vertical movement of the first piston the second References Cited piston and table likewise move vertically. A third pis- UNFTED STATES PATENTS ton is located within the second piston and is movable 3 270 375 9/1966 Young 4/206 relative to the table and strikes the table effecting a 3:311:954 4/1967 Ellms .IIIIIIIITiG4/212 x joking thereof- The Second P Q". is movable 3,478,812 11/1969 Church 164/207 x l/ to effect a joking 0f the table- 3,575,232 4/1971 Young 164/207 3,658,118 4/1972 Abraham 164/29 x 14 6 D'awmg U.S. Patent Nov. 4, 1975 Sheet 1 of4 3,916,983

FIG. I

Sheet 2 of 4 US Patent Nov. 4, 1975 U.S. Patent Nov. 4, 1975 Sheet 3 of4 3,916,983

FIG6

MOL 0 HA RDNESS 0 STRIKE 5 [0 2'0 30 TIME (8E6) 2 3 US. Patent Nov. 4, 1975 Sheet4 f4 3,916,983

FIG. 4

MOLDING MACHINE BACKGROUND OF THE INVENTION The present invention relates to a foundry molding machine, and particularly relates to a foundry molding machine which is capable of effecting a plain jolt operation, as well as a jolt squeeze operation.

Foundry molding machines are known which are capable of providing a plain jolt as well as a jolt squeeze on the mold. In general, such foundry equipment includes a table which supports a mold or the like which is to receive sand and which sand is to be hardened and/or compacted against a pattern. Such machines have been capable of providing a jolting of the sand as well as a jolting of the sand during squeezing of the sand in the mold. Examples of such machines are shown in US. Pat. Nos. 3,658,118; 3,205,442; and 3,461,947.

Typical of such known prior art machines which op- 2 erate on fluid pressure is the fact that the jolting operations, both the plain jolt and the jolt during squeezing, areeffected through the use of substantially the same fluid porting arrangements. As a result, the design of such machines has been compromised with the result SUMMARY OF THE PRESENT INVENTION The present invention constitutes a substantial improvement in the prior art. The present invention comprises a molding machine which may be manufactured at a substantially lower cost than known machines due to the novel construction and mode of operation thereof. In addition, the present machine optimizes the operation of both plain jolt and the jolt during squeeze functions in the machine.

More specifically, applicant has discovered that commercial hardnesses of the sand in a mold can be achieved by a molding machine which does not apply a substantial squeeze pressure on the sand in the mold during the jolting operations. The present invention operates on the basis that during jolting a pressure is applied to the sand which is just sufficient to maintain the sand in contact with the squeeze board during the jolting operation. As a result, applicant has been able to substantially reduce the size of his machine and yet still achieve commercial and substantial hardnesses in the sand without any substantial effect on the time for tial improvement and optimization in the operation of both the plain jolt and the jolt during squeeze, due to a the fact that the functions are performed by separate mechanisms. Thereby, the operation of each may be optimized without compromising the structure of the other.

2 Furthermore, the need for a squeeze cylinder above the mold and above the jolting mechanism is entirely eliminated, and the equivalent structure is integrated into the jolting mechanism, all of which are located beneath the mold.

DESCRIPTION OF THE FIGURES While the above sets forth generally the features and objects of the present invention, these features and objects will be further apparent upon consideration of the detailed description of a foundry molding machine embodying the present invention and which description is made with reference-to the drawings in which:

FIG. 1 is a cross-sectional view of a molding machine embodying the present invention, and showing the parts in a somewhat exploded position;

FIG. 2 is a side view of the molding machine of FIG.

FIG. 3 is a top plan view of a part of the molding machine of FIG. 1;

FIG. 4 is a fragmentary sectional view illustrating parts of the molding machine of FIG. 1 in an elevated position;

FIG. 5 is a view similar to FIG. 4 but illustrating the parts in still another position; and

FIG. 6 is a graph showing operational characteristics of the machine in FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT The present invention, as noted above, relates to a foundry molding machine. The molding machine may be utilized in a variety of different foundry molding environments and systems, and, of course, preferably would be used in a system where the molds or mold parts are automatically fed into and out of the molding machine. Of course, as is well known in the art, in such an overall system the cope and drag of the mold would be formed in separate molding machines and later combined. 1

The molding operation utilizing the present invention is begun by elevating the piston 2 (FIG. 1) within the cylinder 1 by the introduction of pressurized air into the chamber la beneath the piston 2. This motion results in the table 10 moving vertically upwardly and picking up and carrying of the pattern 20 and the flask 11 and upset l2 therewith. Also, a piston 3, located within piston 2, moves upwardly (See FIG. 4). The vertical movement of the upset 12 is restricted and causes a preloading of the springs 13 (See FIG. 2), which hold down the upset 12 in the frame of the machine.

At some point in time before the piston 2 is elevated,

the hopper 19 is filled with sand to an elevation which is controlled by a suitable capacitance probe or other means, not shown, which is of conventional construc tion. When the flask ll, upset l2, and table 10 are in their elevated position, the strike-off 17 is moved to the left or withdrawn from the position-shown in FIG. I and moved to the left from the position, as shown in FIG. 3. When this occurs, the sand which is in the hopper l9 falls into the flask 11 through the upset l2 and falls onto the pattern 20. The amount of sand'which falls is sufficient to fill the flask 11 and to overfill the upset 12, as is conventional.

The strike-off 17 is then returned by cylinder 21 to its position shown in FIG. 3. This, of course, results in some movement of overfilled sand from the upset l2 3 and also allows for the filling of the hopper 19 for the next mold.

As the strike-off 17 is returned to its position shown in FIG. 3, pressurized air is introduced beneath the piston 3 and into the chamber 3a defined between piston 3 and the piston 2. As a result of air pressure being communicated to chamber 3a, the piston 3 is elevated. When this occurs, the upper

abutting surfaces

2b, 3b of the

pistons

2, 3 separate. The raising of piston 3 relative to piston 2 continues until exhaust ports 22, which are located in piston 2, communicate with chamber 3a. These ports 22 communicate atmospheric pressure in any suitable manner. When chamber 30 communicates with the exhaust ports 22 in the piston 2, the chamber 3a is immediately reduced in pressure and the piston then drops and the

surfaces

2b, 3b strike each other. This force causes piston 2 to move downwardly relative to its raised position in which it is illustrated in FIG. 4. Of course, the piston 2 moves downwardly against the pressure in chamber 1a, and as soon as the downward force is dissipated, piston 2 is immediately returned to its position shown in FIG. 4.

In this connection, the piston 2 has a shoulder 2a thereon which engages a cushioning device 7 which is supported on a shoulder 112 on the frame 1. The cushioning device 7 is designed in order to cushion or absorb energy which is applied thereto due to the striking of the cushion device 7 by the piston 2.

The above-described process is repeated, namely, the process of applying a pressure to the chamber 3a causing a raising of the piston 3, the table 10, and the mold l l a slight amount until the ports 22 communicate with chamber 3a causing the chamber 3a to be vented and an immediate lowering or striking of the table on the piston 2. This repetitive process is called plain jolting. As a result of this process, the sand in the mold is hardened or compacted against the top of pattern 20.

The jolt during squeeze operation is effected by a piston which is located within the piston 3. The piston 5 during the plain jolt operation described above rests on a spring 4 which acts between the piston 5 and the base of piston 3. By selecting the proper spring rate 4 and mass of the piston 5, the piston 5 will tend to remain stationary as the piston 3 moves up and down during the plain jolting operation described above, and not strike table or piston 3.

In order to effect the jolt during squeeze operation, the table 10 is slightly raised by the application of air pressure to chamber 3a after ports 22 have been blocked from communication with the atmosphere. The blocking may be accomplished by a suitable valve arrangement 22a (FIG. 1). This results in the parts taking a position as shown in FIG. 5, where the

surfaces

2b, 3b are separated and where the upper face 5a of piston 5 is spaced from the undersurface of table 10.

When in this position, the sand in the mold 11 is held against the squeeze board by the pressure in chamber 3a acting on piston 3. This pressure between the sand in mold l l and squeeze board 18 is substantially less than that commonly used in the art and which is commonly referred to as squeeze pressure. In the present invention, this pressure is just sufficient to maintain the sand in contact with the squeeze board 18 and is somewhat in the order of 12 psi and is below 15 psi. While a pressure does exist on the sand, it is not of the magnitude as in the art, and could just as accurately be termed a mold raising" pressure as a squeeze pressure.

Due to the fact that this pressure is substantially lower than is provided by any machines presently known to applicant, the diameter of the pistons, and particularly of piston 3, may be substantially reduced from that known in the art and the entire size of the mechanism for controlling the raising movement and the jolting of the table 10 may be of substantially small size, thus greatly reducing the cost involved in the manufacture of the machine.

While the table 10 is being raised by movement of the piston 3 from its position of FIG. 4 to its position in FIG. 5, controlled air pressure is introduced beneath the piston 5 into the chamber 5b causing the piston 5 to rise with the result that the upper face 5a of the piston 5 contacts the lower surface of the table 10. The pressure in chamber 5b is then maintained by a suitable pressure regulator (not shown) and pressure is communicated into the chamber 5c above the piston 5 causing the piston 5 to move downwardly until exhaust ports 25 in piston 3 are communicated with chamber 5c. As soon as exhaust ports 25 in piston 3 communicate with chamber 50, the pressure in chamber 5c is vented and the piston 5 is immediately propelled upwardly by the combined force of the pressure in the chamber 5b and the spring 4. The upward propelling force causes the piston 5, and mainly the upper face 5 thereof, to strike the underface of the table 10 which creates a high peak force. This process is repeated a sufficient number of times to harden the sand to a suitable hardness level, and this process has the same effect as what the art terms a simultaneous jolt squeeze. This effect is obtained, even though it should be understood that the pressure on the sand due to pressure acting on piston 3 is at a substantially lower level than any squeezing action known in the art.

It should be clearly understood that applicant has discovered, and a series of tests support the fact, that a high squeeze pressure provided by the piston 3 is unnecessary in order to provide a sufficient mold sand hardness within commercial times for effecting such. This is borne out by the graph of FIG. 6 which plots mold hardness versus number of strikes of the piston 5 as well as time. It can be readily seen that in one or two seconds and with three to twenty strikes of the piston 5, mold hardnesses in the range, of -95 can be effected, even though a very low pressure of not greater than 15 psi and preferably in the order of 12 psi is applied to the sand, and the pressure in the tests which have been conducted has been as low as 0.9 psi. This discovery enables applicant to construct a molding machine which is substantially smaller than those in the prior art without sacrificing time or effect. In addition, it should be apparent that the

ports

22, 25 are completely separated in applicants operation and that the plain jolt is effected by a fluid arrangement which is separate from the so-called jolt squeeze arrangement. As a result, the design of these parts and relative positioning and sizing, etc., of these parts may be effected completely independently of each other and the relative sizing and location of the mechanism and parts for plain jolt may be completely separate and independent of those for purposes of providing a jolt during squeeze. More specifically, the mechanism, namely, the chamber 50 and the ports 25 as well as the particular distance that the piston 5 must move before ports 25 open, are completely independent of the mechanism which effects the plain jolt and, in fact, even pressure in the chamber 5c is separate from the pressure which is in chamber 3a, and accordingly the'mechanism for effecting the simultaneous jolt during squeeze may be completely engineered independently. As a result,v these .particular structures can be engineered to their optimum designs.

Moreover, it should be clear that all of the operating mechanisms, namely,

pistons

2, 3 and 5, are located in one integrated structure beneath the table. 10, and that no squeeze piston or the like is located above. thetable 10. It should, also be noted that the table. is releasably connected to the upper endof piston 3 by aplurality of fasteners 30.- This enables the table to be replaced with anotherin the event-mold sizes orthe like which are used change. g I

After the sand has been hardened in the mold, all air cylinders beneath the table 10 are exhausted and this allows the-table to descend on guide rods 26, 26( which effect the guiding movement of the table. The guide rods 26 also control the downward movement of the table along with oil control cylinders 27. The oil control cylinders allow the mold and pattern to part slowly for about one inch and then rapidly for the remainder of the stroke. This is called respectively slow and fast draw. Of course, once this occurs the pattern remains on the .table 10 and the mold is stripped or held above the table 10 so that it may be moved from the molding machine for purposes of further processing, which will not be described herein.

From the above, it should be apparent that applicant has provided a substantially improved molding machine which does not sacrifice any of the desired operable characteristics of such machines which are presently commercially known.

Having described my invention, 1 claim:

1. A molding machine comprising a table for supporting a mold pattern and a mold, a cylinder located beneath said table, a first piston located with said cylinder and movable vertically therein to a limit position in which surfaces of said cylinder and first piston are in contact, a second piston carried within said first piston and means interconnecting the second piston with the table and with said first piston so that on vertical movement of the first piston the second piston likewise moves vertically, a first fluid chamber located between said first and second pistons for effecting movement of said second piston relative to said first piston on the application of fluid pressure thereto, and a third piston located within said second piston and movable relative to said table to strike said table to effect jolting thereof.

2. A molding machine as defined in claim 1 wherein said surfaces of said cylinder and first piston comprise shoulder portions thereof with one of said shoulder portions including energy-absorbing means.

3. A molding machine as defined in claim 1 wherein said first piston has venting ports therein and said first fluid chamber communicates with said ports upon slight relative movement of said second piston relative to said first piston to vent said chamber and cause jolting of said mold due to striking of abutting surfaces of said first and second pistons.

4. A molding machine as defined in claim 3 wherein a second fluid chamber is provided between said table and said third piston, fluid pressure when applied to said second fluid chamber causing movement of said third piston away from said table, said second piston having venting ports which communicate with said second fluid chamber upon relative movement of said third piston and said second piston, and fluid pressure in said first fluid chamber returning said third piston ton construction and means defining a first chamber for effecting vertical movement of said piston to effect vertical movement of said flask and sand and first vent means for venting the pressure in said first chamber uponvertical movement of said pistonfsaid second means comprising a second piston and a second chamber into which fluid pressure is applied and second vent means for venting the pressure in said second fluid chamber'when said second piston is moved a predetermined distance, relative to the table, and means for effecting a return of the second piston into striking contact'with the table.' i

7. A molding machine as defined in claim 6 further including means for blocking said first vent 'rneansfisaid first chamber and said first piston being sized toapply a pressure on the sandagainst said squeeze board in the order of 12 psi.

8. A molding machine comprising means for supporting a pattern and a flask for receiving sand, first means for effecting a plain jolt of said sandin the flask, second means for effecting a simultaneous squeeze jolt of the sand in the flask, said first means comprising a first piston construction and me ans defining a first chamber for effecting vertical movement of said piston to effect vertical movement of said flask and sand and first vent means for venting the pressure in said first chamber upon vertical movement of said piston, said second means comprising a second piston and a second chamber into which fluid pressure is applied and second vent means for venting the pressure in said second fluid chamber when said second piston is moved a predetermined distance relative to the table, and means for effecting a return of the second piston into striking contact with the table, said means defining a first chamber comprising a third piston movable vertically and having an abutting surface engagement with said first piston to raise said first piston upon vertical movement thereof, and said first vent means comprising first venting ports located in said third piston.

9. A molding machine as defined in claim 8 further including means for blocking said first vent means so that upon application of pressure to said first chamber said first piston may raise said table without venting of said chamber to squeeze sand in the mold against a squeeze board.

10. A molding machine as defined in claim 9 wherein said second chamber is located between said table and said second piston and said second vent means comprises second venting ports located in said first piston.

11. A molding machine comprising a support for a pattern and a mold which receives sand, a squeeze board, means for effecting a squeezing of the sand in the flask against said squeeze board at a pressure not greaterthan 15 psi, said means comprising a first piston for carrying said flask and for squeezing said flask against said squeeze board, means for effecting a jolting of the table while the sand and squeeze board are under said pressure relationship established through said first piston including a second piston located within said first piston and movable relative thereto under the influence of pressure, and means providing a fluid pressure for propelling said second piston into contact with the pattern support to effect a jolting of the pattern support through the contact of the second piston therewith while the not greater than psi pressure is maintained on the sand in the mold.

12. A molding machine as defined in claim 11 comprising a third piston in which said first piston is located and means defining a fluid pressure chamber for fluid pressure for raising said third piston, said third piston and said first piston having abutting surfaces so as to effect raising of said first piston with said third piston.

13. A molding machine comprising a support for a pattern and a mold which receives sand, a squeeze board, means for effecting a squeezing of the sand in the flask against said squeeze board at a pressure not greater than 15 psi. said means comprising a first piston, means for effecting a jolting of the table while the sand and squeeze board are under said pressure relationship including a second piston located within said first piston and movable relative thereto under the influence of pressure, means providing a fluid pressure for propelling said second piston into contact with the pattern support to effect a jolting of the pattern support through the contact of the second piston therewith while the not greater than 15 psi pressure is maintained on the sand in the mold, a third piston in which said 8 first piston is located, means defining a fluid pressure chamber for fluid pressure for raising said third piston, said third piston and said first piston having abutting surfaces so as to effect raising of said first piston with said third piston, and means for effecting a jolting of said table by a raising and lowering movement of said first piston and movement of said abutting surfaces into and out of contact.

14. A molding machine comprising a support for a pattern and a mold which receives sand, a squeeze board, means for effecting a squeezing of the sand in the flask against said squeeze board at a pressure not greater than 15 psi, said means comprising a first piston, means for effecting a jolting of the table while the sand and squeeze board are under said pressure relationship including a second piston located within said first piston and movable relative thereto under the influence of pressure, and means providing a fluid pressure for propelling said second piston into contact with the pattern support to effect a jolting of the pattern support through the contact of the second piston therewith while the not greater than 15 psi pressure is maintained on the sand in the mold, said means for providing a fluid pressure for propelling said second piston upwardly comprising a fluid pressure chamber located between said first and second pistons and a spring acting between said first and second pistons urging said second piston upwardly.

Claims

4. A molding machine as defined in claim 3 wherein a second fluid chamber is provided between said table and said third piston, fluid pressure when applied to said second fluid chamber causing movement of said third piston away from said table, said second piston having venting ports which communicate with said second fluid chamber upon relative movement of said third piston and said second piston, and fluid pressure in said first fluid chamber returning said third piston into striking contact with said table when said second chamber is vented.

5. A molding machine as defined in claim 1 wherein said second piston is constructed to apply a force no greater than 15 psi to the sand in the mold.

6. A molding machine comprising means for supporting a pattern and a flask for receiving sand, first means for effecting a plain jolt of said sand in the flask, second means for effecting a simultaneous squeeze jolt of the sand in the flask, said first means comprising a first piston construction and means defining a first chamber for effecting vertical movement of said piston to effect vertical movement of said flask and sand and first vent means for venting the pressure in said first chamber upon vertical movement of said piston, said second means comprising a second piston and a second chamber into which fluid pressure is applied and second vent means for venting the pressure in said second fluid chamber when said second piston is moved a predetermined distance relative to the table, and means for effecting a return of the second piston into striking contact with the table.

7. A molding machine as defined in claim 6 further including means for blocking said first vent means, said first chamber and said first piston being sized to apply a pressure on the sand against said squeeze board in the order of 12 psi.

8. A molding machine comprising means for supporting a pattern and a flask for receiving sand, first means for effecting a plain jolt of saId sand in the flask, second means for effecting a simultaneous squeeze jolt of the sand in the flask, said first means comprising a first piston construction and means defining a first chamber for effecting vertical movement of said piston to effect vertical movement of said flask and sand and first vent means for venting the pressure in said first chamber upon vertical movement of said piston, said second means comprising a second piston and a second chamber into which fluid pressure is applied and second vent means for venting the pressure in said second fluid chamber when said second piston is moved a predetermined distance relative to the table, and means for effecting a return of the second piston into striking contact with the table, said means defining a first chamber comprising a third piston movable vertically and having an abutting surface engagement with said first piston to raise said first piston upon vertical movement thereof, and said first vent means comprising first venting ports located in said third piston.

11. A molding machine comprising a support for a pattern and a mold which receives sand, a squeeze board, means for effecting a squeezing of the sand in the flask against said squeeze board at a pressure not greater than 15 psi, said means comprising a first piston for carrying said flask and for squeezing said flask against said squeeze board, means for effecting a jolting of the table while the sand and squeeze board are under said pressure relationship established through said first piston including a second piston located within said first piston and movable relative thereto under the influence of pressure, and means providing a fluid pressure for propelling said second piston into contact with the pattern support to effect a jolting of the pattern support through the contact of the second piston therewith while the not greater than 15 psi pressure is maintained on the sand in the mold.

13. A molding machine comprising a support for a pattern and a mold which receives sand, a squeeze board, means for effecting a squeezing of the sand in the flask against said squeeze board at a pressure not greater than 15 psi, said means comprising a first piston, means for effecting a jolting of the table while the sand and squeeze board are under said pressure relationship including a second piston located within said first piston and movable relative thereto under the influence of pressure, means providing a fluid pressure for propelling said second piston into contact with the pattern support to effect a jolting of the pattern support through the contact of the second piston therewith while the not greater than 15 psi pressure is maintained on the sand in the mold, a third piston in which said first piston is located, means defining a fluid pressure chamber for fluid pressure for raising said third piston, said third piston and said first piston having abutting surfaces so as to effect raising of said first piston with said third piston, and means for effecting a jolting of said table by a raising and lowering movement of said first piston and movement of said abutting surfaces into and out of contact.